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The next generation of Neutrino telescopes -ICECUBE Design and Performance, Science Potential. Albrecht Karle University of Wisconsin-Madison karle@alizarin.physics.wisc.edu. Neutrino 2002 Munich. The IceCube Collaboration.

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the next generation of neutrino telescopes icecube design and performance science potential

The next generation of Neutrino telescopes -ICECUBEDesign and Performance, Science Potential

Albrecht Karle

University of Wisconsin-Madison

karle@alizarin.physics.wisc.edu

Neutrino 2002

Munich

the icecube collaboration
The IceCube Collaboration

Institutions: 11 US, 9 European institutions and 1 Japanese institution; ≈110 people

  • Bartol Research Institute, University of Delaware
  • BUGH Wuppertal, Germany
  • Universite Libre de Bruxelles, Brussels, Belgium
  • CTSPS, Clark-Atlanta University, Atlanta USA
  • DESY-Zeuthen, Zeuthen, Germany
  • Institute for Advanced Study, Princeton, USA
  • Dept. of Technology, Kalmar University, Kalmar, Sweden
  • Lawrence Berkeley National Laboratory, Berkeley, USA
  • Department of Physics, Southern University and A\&M College, Baton Rouge, LA, USA
  • Dept. of Physics, UC Berkeley, USA
  • Institute of Physics, University of Mainz, Mainz, Germany
  • University of Mons-Hainaut, Mons, Belgium
  • Dept. of Physics and Astronomy, University of Pennsylvania, Philadelphia, USA
  • Dept. of Astronomy, Dept. of Physics, SSEC, University of Wisconsin, Madison, USA
  • Physics Department, University of Wisconsin, River Falls, USA
  • Division of High Energy Physics, Uppsala University, Uppsala, Sweden
  • Fysikum, Stockholm University, Stockholm, Sweden
  • University of Alabama
  • Vrije Universiteit Brussel, Brussel, Belgium
  • Chiba University, Japan
outline of talk
Overview

Muon neutrinos from:

a) diffuse sources

b) point sources

c) Gamma ray bursts

Electron Neutrinos: Cascades

Tau Neutrinos

The surface component: IceTop

Detector: Optical sensor

Summary

Outline of Talk
icecube has been designed as a discovery instrument with improved
IceCube has been designed as a discovery instrument with improved:
  • telescope area
  • detection volume
  • energy measurement of secondary muons and electromagnetic showers
  • identification of neutrino flavor
  • angular resolution
icecube

IceTop

AMANDA

South Pole

Skiway

1400 m

2400 m

IceCube
  • 80 Strings
  • 4800 PMT
  • Instrumented volume: 1 km3 (1 Gt)
project status
Project status
  • Approved by the National Science Board
  • Startup funding is allocated.
  • Construction is in preparation (Drill, OM design, OM production, DAQ and test facilities).
  • Construction start in 04/05; possibly a few initial strings in 03/04.
flavours and energy ranges
Filled area: particle id, direction, energy

Shaded area: energy only

Detect neutrinos of all flavours at energies from 107 eV (SN) to 1020 eV

- flavours and energy ranges
neutrino sky as seen by amanda
Monte Carlo methods are verified on data.Neutrino sky as seen by AMANDA

events

Methods are not yet optimized and

fully developed for high energies.

cos 

track reconstruction in low noise environment

AMANDA-II

Track reconstruction in low noise environment

10 TeV

  • Typical event: 30 - 100 PMT fired
  • Track length: 0.5 - 1.5 km
  • Flight time: ≈4 µsecs
  • Accidental noise pulses:

10 p.e. / 5000 PMT/4µsec

1 km

angular resolution 1 med
Resolution ≈ 0.8 deg (median)

Improves slightly with energy

Better near horizon: ≈0.7° (Sample more strings)

Angular resolution < 1° (med)

Search bin ≈ 1.0°

Solid angle: 2π/6500

effective area for muons
Trigger: allows non contained events

Quality cuts: for background rejection

Point source selection: soft energy cut for atmos. neutrino rejection (Assumed spectrum: E-2, time of exposure 1 year)

Effective area for muons

Geometric detector area = 1km2

Eff. area = Agen* (Ndet./Ngen)

Efficiency ≈ effective area/km2

Muon energy is the energy

at closest approach to

the detector

log10(E/GeV)

effective area vs cos
Effective Area vs. cos()

Effective areas are given

after quality cuts

(including up/down separation where needed)

Muon energy

Note that the detector is sensitive to downward going muons

at energies above 1 PeV

point sources event rates
Point sources: event rates

Flux equal to current AMANDA limit

dN/dE = 10-6*E-2/(cm2 sec GeV)

compare to mrk 501 gamma ray flux
Compare to Mrk 501 gamma ray flux

Field of view:

Continuous 24 h x 2 p sr

(northern sky)

AMANDA

prelim. limit

Sensitivity of

3 years of IceCube

search for diffuse n fluxes
Method:

Assume a diffuse neutrino flux (Hypothesis), e.g. the current AMANDA limit:

dN/dE = 10-6*E-2/(cm2 sec GeV sr)

--> 11,500 events /year

The background is the atmospheric neutrino flux (after quality cuts): = 100,000 events / year

Apply energy cut.

Search for diffuse n-fluxes

Atmospheric n

E-2 flux

True neutrino energy

slide17

Eµ=10 TeV ≈ 90 hits

Eµ=6 PeV ≈ 1000 hits

Energy reconstruction

Small detectors: Muon energy is difficult to measure because of fluctuations in dE/dx

IceCube: Integration over large sampling+ scattering of light reduces the

fluctutions energy loss.

event rates before and after energy cut
Event rates before and after energy cut

Note:

Neutrinos from Charm production included

according to: Thunman, Ingelmann, Gondolo,

Astropart. Phys. 5:309-332,1996

diffuse flux 3 years of icecube
Optimize energy cut.

Sensitivity of IceCube after 3 years of operation (90% c.l.):

dN/dEn ≤ 4.8 x 10-9 * E-2/(cm2 sec GeV)

Diffuse flux, 3 years of IceCube
slide20

1 pp core AGN (Nellen)

2 p core AGN

Stecker & Salomon)

3 p „maximum model“

(Mannheim et al.)

4 p blazar jets (Mannh)

5 p AGN

(Rachen & Biermann)

6 pp AGN (Mannheim)

7 GRB

(Waxman & Bahcall)

8 TD (Sigl)

Example: Diffuse Fluxes - Predictions and Limits

from

Mannheim & Learned,2000

Macro

Baikal

Amanda

IceCube

Sensitivity after 3 years

wimps from sun earth
WIMPs from Sun/Earth

Look for excess of muons from the direction of the sun or the center of the earth

wimps from the sun with icecube
WIMPs from the Sun with IceCube

J. Edsjö, 2000

  • IceCube will significantly improve the sensitivity.
  • Similar sensitivity to GENIUS, …
neutrinos from gamma ray bursts
Reject background by:

Energy (number of fired PMT)

Angle (circular bin of 1º radius)

Time (≈ 10 sec/ GRB, coincident to known GRB, gamma ray signal, e.g. from satellite detector)

Neutrinos from Gamma Ray Bursts
neutrinos from gamma ray bursts24
For 1000 GRB observed:

Expected signal: 11 upgoing muon events

Expected background: 0.05 events

Neutrinos from Gamma Ray Bursts

Essentially background free detector:

Only 200 GRB needed to detect standard

fireball prediction (Waxman/Bahcall 99)

cascade event
Cascade event

Energy = 375 TeV

ne + N --> e- + X

  • The length of the actual cascade, ≈ 10 m, is small compared to the spacing of sensors
  • ==> ≈ roughly spherical density distribution of light
  • 1 PeV ≈ 500 m diameter
  • Local energy deposition = good energy resolution of neutrino energy
event rates of cascades n e
Event rates of cascades (ne)

Assumed flux: dN/dE = 10-7*E-2/(cm2 sec GeV sr)

Rates at trigger level

Effective volume after background rejection:

1 km3 for E>30TeV

double bang

t + N --> t- + X

t + X (82%)

Double Bang

Learned, Pakvasa, 1995

Regeneration makes Earth quasi

transparent for high energie ;

(Halzen, Salzberg 1998, …)

Also enhanced muon flux due to

Secondary µ, and nµ

(Beacom et al.., astro/ph 0111482)

E << 1PeV: Single cascade

(2 cascades coincide)

E ≈ 1PeV: Double bang

E >> 1 PeV: partially contained

(reconstruct incoming tau track and cascade from decay)

at e pev partially contained
The incoming tau radiates little light.

The energy of the second cascade can be measured with high precision.

Signature: Relatively low energy loss incoming track: would be much brighter than the tau (compare to the PeV muon event shown before)

atE>PeV: Partially contained

Photoelectron density

Timing, realistic spacing

Result: high eff. Volume;

Only second bang needs to be seen in Ice3

10-20 OM early hits measuring the incoming t-track

density profile of double bang event

300 m

0 m

-300 m

0 m

300 m

Density profile of double bang event

Shown is the expected photoelectron signal density of a tau event.

The first ntinteraction is at z=0, the second one at ≈225m.

The diagram spans about 400m x 800m.

105

103

10

10-1

Photoelectrons/PMT

capture waveform information mc
Complex waveforms provide additional information Capture Waveform information (MC)

E=10 PeV

String 5

String 4

String 3

String 1

String 2

Events /

10 nsec

0 - 4 µsec

daq design digital optical module pmt pulses are digitized in the ice
Design parameters:

Time resolution:≤ 5 nsec (system level)

Dynamic range: 200 photoelectrons/15 nsec

(Integrated dynamic range: > 2000 photoelectrons)

Digitization depth: 4 µsec.

Noise rate in situ: ≤500 Hz

DAQ design: Digital Optical Module- PMT pulses are digitized in the Ice

DOM

For more information

on the Digital Optical Module:

see poster by R. Stokstad et al.

33 cm

coincident events
Two functions

veto and calibration

cosmic-ray physics

Energy range:

~3 x 1014 -- 1018 eV

few to thousands of muons per event

Measure:

Shower size at surface

High energy muon component in ice

Large solid angle

One IceTop station per hole

~ 0.5 sr for C-R physics with “contained” trajectories

Larger aperture as veto

IceTop

Coincident events
schematic of icetop detector
Two Ice Cherenkov tanks at top of each IceCube hole

Each 3.6 m2; local coincidence for muon vs. shower discrimination

Calibration with single muons @ ~1KHz per tank

Integrated into IceCube

construction

trigger

data acquisition

Heritage:

Haverah Park

Auger

Schematic of IceTop detector

Single 

expectation for coincident events
~109 IceTop-IceCube coincidences/year

Calibration beam for IceCube

~100/day with multi-TeV  in IceCube

Air shower physics to 1018 eV

Expectation for coincident events

Some numbers:

Shower energy

Number of muons / shower

Number of events / year

spase amanda energy resolution of air shower primary
SPASE - AMANDA: Energy resolution of air shower primary

Energy resolution of air

shower primary for 1<E/PeV<10:

sE ≈ 7% log(E)

(Mass independent; based on MC)

Proton

Iron

5 6 7 8

Log(E_true)

5 6 7 8

Log(E_reconstructed)

measuring mass and energy of cosmic ray primary particle

Iron

Proton

AMANDA (number of muons)

log(E/GeV)

SPASEII (number of electrons)

Measuring mass and energy of cosmic ray primary particle

Unfolding energy

and mass using

SPASE and AMANDA

slide38

Supernova detection in IceCube

  • ne + p --> n + e+ (10-40 MeV)
  • Low PMT noise (<500Hz) increase due to the positrons
  • AMANDA/IceCube records noise on the PMTs over 0.5 sec and summing up total rate over 10 sec intervals.
  • Detectors to be connected to Supernova Early Warning System

MC

AMANDA

IceCube

construction 11 2003 01 2009
Construction: 11/2003-01/2009

Grid

North

100 m

AMANDA

South Pole

SPASE-2

IceCube

Dome

Skiway

south pole
South Pole

Dark sector

Skiway

AMANDA

Dome

IceCube

project status41
Project status
  • Approved by the National Science Board
  • Startup funding is allocated.
  • Construction is in preparation (Enhanced Hotwater Drill, OM design, OM production facilties, DAQ and test facilities).
  • Construction start in 04/05; possibly a few initial strings in 03/04.
  • Then 16 strings per season, increased rate may be possible.
summary
Summary
  • IceCube array allows
    • Very good event reconstruction (E,).
    • High sensitivity to muon-, electron-, tau-neutrinos.
    • Particle identification over wide energy range.
  • IceCube is a multipurpose detector covering a wide range of energies, signals, discovery potentials.
  • Size and quality of information provides sensitivity in discovery range.
  • Construction is in preparation.